Physiological Limits to Hibernation in Large Mammals: Energetics, Body Composition, and Sleep in Black Bears (SGER)

University Of Alaska Fairbanks Campus, Fairbanks AK

Investigators

Abstract

Abstract OPP-00-76039 Barnes The Principal Investigator will take advantage of an unexpected opportunity for investigating hibernation behavior, physiology, and neurobiology in hibernating black bears, Ursus americanus. The Alaska Department of Fish and Game will provide two "trouble" bears that are just entering hibernation. These bears would be destroyed because they have a history of endangering people. The Principal Investigator has outdoor artificial dens and preliminary that suggests that large mammalian hibernators achieve energy savings with very different physiological mechanisms than do small hibernators, such as arctic ground squirrels, Spennophilus parryii. For example, bears substantially reduce their metabolic rate and do not fast for six months. They achieve this with only a 3-5oC reduction in body temperature (versus a 40 oC decline in ground squirrels). They also remain almost continuously in slow-wave sleep. The Principal Investigator will measure these variables using state-of-the-art telemetry, which allows them to continuously monitor body temperatures, brain waves, EKG, and rates of oxygen consumption in untethered black bears hibernating in natural conditions for six months. There is now an unexpected opportunity to extend these measurements to a female that is likely to be pregnant. This hibernation physiology has never been studied in a hibernating bear that will gestate, give birth, and nurse an offspring. The Principal Investigator will collaborate with Dr. Oivind Toien, previously with the Norsk Polar Institute. Dr. Toien is critical to the study because of his expertise in respirometry and telemetry.